Back gear for lathe-heads and the like.



' c, r. DAVIS. BACK GEAR FOR LAIHE HEADS AND THE LIKE;

. nrrucmon mz-n rm. :2. 1914.

1,249,905. Patented Dec. 11,1917.

I l l i l x "T w? Q n R I a o I a 1 0 a g R N @vwentoi W Chariesif'flavs lll till

ll h till cit-tannins navts, or noonns'rnn, n'nw roan, aesren'on, rat

to navrs ivtaon'rn'n root nominative, site, or near HAWK CitEltItt FUR LllTI-lIE-HEADEE .lthll) THE Illdlilillfi.

Application filed. itiebruary 155, 1914i.

To (ZZZ whom it may concern lie it known that l, (Maniacs l Davis, of Rochester, in the coi'uity of lllhiuroe and tdtate of New York, have invented certain new and useful Improvements in Back Gear for Latheldleads and the like: and l do hereby declare the following to be a tall, clear, and exact description ot the same, reference being had to the accompanying drawings, i'torminp; a part of this specification, and to the reference-numorals marked thereon.

llhe present invention relates to a back ,e'ear mechanism for lathe heads and similar machinery where it is necessary to shift :trom fast to slow speed for certain kinds of work, and it has for its primary object to provide a construction whereby a more compact arrangement is obtained with nsequent advantages in manufacture and use of the ma chine. it further purpose of: the invention resides in so disposing the parts as to reduce to minimum the to sional strainsthat are usually present in this type of mecha nism and to eliminate the chattering and resulting loss of power which present in the usual backv gear drive. To these and other ends the invention consists in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

in the drawings:

Figure 1 is a view in side elevation, partly in longitudinal vertical section, showing; a portion of a lathe head equipped with a preterred arrangement of the invention, and

Fig. 2 is a transverse vertical sectional view.

Similar reference numerals throughout the several figures indicate the same parts.

in the present embodiment, l designates the frame of the machine provided with suitable bearings 2 in which is journaled the spindle 3 receiving power from a driving; member including a cone-pulley ll, at ditt'erent speeds, as will presently appear more clearly. The driving member embracing the cone-pulley 4:, is loosely mounted on the spindle 3 and is provided with a collar 5 upon which is keyed a pinion 6. The collar 5 is also provided with an extension 7 carrying a plate E5 fixed thereon and pro.

Specification of Letters ratent.

llda'tcnt cd time, till, 1917 serial Ito. siesta.

vided with one or more openings ll to" a purpose that will be explained.

drrangred adjacent to the collar 5 on the spindle, is a driven member consistingof a gear wheel which carries one or inore locking pins 11. that are slidable transversely thereoi and adapted to engage the openings 9 in the plate 8 whereby to drive the near 10 and the spindle at the same speed as the driving member. When it is desired to retate the spindle at a lower speed, the pins 11 are withdrawn from looking ei'lgrapgeineut with the plate 8, as shown in 1, permittingthe driving member to tiirn independently of the gear 10. llnder such conditions, the spindle is driven through a back gear arrangement which reduces the speed, and to this end, there is provided an oscil latory or pivotally mounted trams 12, mounted in bearings 13 and carrvinp; a finedly mounted arbor 141:. rtrrai nd on said arbor 1.4: are transmission devices disposed in close proximity, and preferably in junta position to each other, which are adapted to transmit power fii'l'Olll the driving member to the driven member a t a reduced speed, and preferably consisting oil) the gear arranged to engage the pinion G, and a pinion 16 arranged to engage the gear 10. The gear 15 and pinion 16 are rotatable together on the arbor 14-, and are preferably formed integral, although there are other ways in which they may be constructed, so long they are maintained in close relation to each other.

The frame 12 is movable to shift the transmission devices 15 and 16 into or out of engagement with the driving; and driven members, and in the present construction there is shown a convenient arrangement for accomplishing this consisting ot areciprocatory operating; spindle 17 which carries a cam projection 18 arranged to engag a lop; 19 on. the frame 12, so that as the spindle 17 is moved inwardly or outwardly ot the frame 1, the frame 12 is elevated or lowered. 2O designates a handle tor operating; the spindle 1'? which is slidable in hearings in the frame it and held against rotation by a key 21. lit will be obvious that the raising; and lowering of the frame 12 may be accomplished in a different manner than by the means just described, and any convenient lidd ltllfi mechanism for elevating or lowering the transmission devices into or out of engagement with the driving or driven members is considered within the scope and purpose of the invention.

It is to be noted that the transmission devices are arranged beneath the spindle and the driving and driven members, and this is deemed an important feature of the invention as it affords a much more compact arrangement and eliminates any shaftiug or gearing arranged laterally of the spindle and driving member. Furthermore, by disposing the transmission devices in close proximity to each other instead of spacing them at some considerable distance along a shaft, a much more rigid and powerful structure is produced, that is vastly better capable of withstanding the strain to which the parts are subjected in changing from one speed to another. The arrangement affords an extremely simple structure that can be operated quite readily under all conditions and presents little possibility of the parts failing in their proper and most effective cooperation.

I claim as my invention:

1. In a back gear for lathe heads, the combination with a lathe bed having a head stock, a rotary tool carrying spindle journaled therein, and a driving gear wheel fixed to the spindle, a driven pulley journaled on the spindle, a pinion fixed to the pulley adjacent the gear wheel, and means for detachably connecting said combined pulley and pinion with the gear wheel, of a yoke frame pivotally supported in the head Copies of this patent may be obtained for five cents stock on bearings located beneath and at one side of the axis of the spindle and ha ing a depending operating portion projecting into the bed, a transmission gear wheel and pinion jonrnaled on the yoke frame and adapted to cooperate with the gear wheel on the spindle and the pinion en the pulley and a device accessible at the forward side of the lathe bed beneath the head stock and cooperating with the operating portion of the yoke frame to operate it to adjust the transmission gear and pinion into and out of operative position.

2. In a lathe, the combination with a bed frame, a head stock at one end thereof, a tool carrying spindle journaled in the hind stock, a driven gear wheel fixed to the spindle, a driving pinion loosely carried on the latter, and means for detachably interlocking the gear wheel and pinion together.oi a yoke frame pivoted to the head stock below and in rear of the axis of the spindle and having :1 depending operating end extending into the bed frame, a transmission gear wheel and pinion journaled on the yoke and adapted to be moved thereby into and out of operativc engagement with the pinion and gear wheel, respectively, on the spindle, and a reciprocating shaft guided in the bed and having a lug cooperating with the operating portion of the yoke to raise and lower the latter.

CHARLES F. DAVIS.

each, by addressing the Commissioner of Yatenca Washington, D. G. 

